Adding voltmeter to car

[Steve Firth]

Keith wrote:

[snip]

Don't bother with a voltmeter. A far better investment is a set of
jumper cables.

That's kinda like suggggesting one wear Depends instead of stopping at the
a rest area on the highway.

Can you say that again in English?

 

[chuck]

Keith wrote:

On Thu, 13 Apr 2006 22:17:49 +0000, chuck wrote:


Andy wrote:

I am in the UK and have a 1.3 litre Mazda which is over 10 years
old.

I have been reading a few web pages which made reference to the
reader's car which "may have a dashmoard voltmeter".

Is a voltmeter actually all that useful to see tjings like what
the condition the battery is in and how the battery copes and how
it is charging?

Can I permanently connect my cheap handheld digital voltmeter to
the car battery. I would then mount the meter permanently on the
dashboard.

Is there a real danger that the meter will get damaged by various
current or voltage surges? Is it good enough protection to have a
quick blow fuse in line with the test lead going to the positive
terminal?

Thanks




Don't bother with a voltmeter. A far better investment is a set of
jumper cables.


That's kinda like suggggesting one wear Depends instead of stopping at the
a rest area on the highway.

Nothing of the sort, really. If one is curious about battery charging
and discharging principles, then a voltmeter, ammeter, thermometer,
hydrometer, a lot of time, and a text book will prove rewarding.

But if the concern is to obtain early warning of an impending
battery/alternator/regulator/belt failure so as to avoid being caught on
the road without an electrical system, then most of us would benefit far
more from the jumper cable. ;-)

If the voltmeter would "prevent" such a breakdown by giving advance
warning of sufficiently high certainty to result in an immediate trip to
a competent repair technician, then it would be a good thing.
Unfortunately, even if the meter did so indicate, immediately and
unambiguously, one might be on the road far from any repair facilities
at the time of the indication, in which case jumper cables would be most
useful.

I wonder how many of us have looked at a voltmeter, concluded that
something was wrong, replaced the battery, and found that the world was
good again. Compare that number to those of us who, upon noticing a
strange reading of the meter, made a mental note to keep an eye on the
meter, and then eventually found ourselves with a dead battery. From the
postings, it seems not all of us would be able to interpret various
meter indications even if we had them before us.

Unlike the rest area "fix", a voltmeter will not "ward off" a leaking
battery failure. ;-)

Chuck

 

[Gary Schafer]

On Sun, 23 Apr 2006 12:54:56 GMT, chuck <nospam@nospam.net> wrote:

Keith wrote:
On Thu, 13 Apr 2006 22:17:49 +0000, chuck wrote:


Andy wrote:

I am in the UK and have a 1.3 litre Mazda which is over 10 years
old.

I have been reading a few web pages which made reference to the
reader's car which "may have a dashmoard voltmeter".

Is a voltmeter actually all that useful to see tjings like what
the condition the battery is in and how the battery copes and how
it is charging?

Can I permanently connect my cheap handheld digital voltmeter to
the car battery. I would then mount the meter permanently on the
dashboard.

Is there a real danger that the meter will get damaged by various
current or voltage surges? Is it good enough protection to have a
quick blow fuse in line with the test lead going to the positive
terminal?

Thanks




Don't bother with a voltmeter. A far better investment is a set of
jumper cables.


That's kinda like suggggesting one wear Depends instead of stopping at the
a rest area on the highway.



Nothing of the sort, really. If one is curious about battery charging
and discharging principles, then a voltmeter, ammeter, thermometer,
hydrometer, a lot of time, and a text book will prove rewarding.

But if the concern is to obtain early warning of an impending
battery/alternator/regulator/belt failure so as to avoid being caught on
the road without an electrical system, then most of us would benefit far
more from the jumper cable. ;-)

If the voltmeter would "prevent" such a breakdown by giving advance
warning of sufficiently high certainty to result in an immediate trip to
a competent repair technician, then it would be a good thing.
Unfortunately, even if the meter did so indicate, immediately and
unambiguously, one might be on the road far from any repair facilities
at the time of the indication, in which case jumper cables would be most
useful.

I wonder how many of us have looked at a voltmeter, concluded that
something was wrong, replaced the battery, and found that the world was
good again. Compare that number to those of us who, upon noticing a
strange reading of the meter, made a mental note to keep an eye on the
meter, and then eventually found ourselves with a dead battery. From the
postings, it seems not all of us would be able to interpret various
meter indications even if we had them before us.

Unlike the rest area "fix", a voltmeter will not "ward off" a leaking
battery failure. ;-)

Chuck

We might just as well throw out the fuel gauge then too. Just looking
at it will not keep us from running out of fuel. Might be better to
just carry a spare can of with us.

Like the voltmeter, if one doesn't know how to interpret the fuel
gauge properly it does no good to have it aboard. Admittedly the
voltmeter is a little more complicated to interpret than the fuel
gauge but it can also be a valuable instrument.

Regards
Gary

 

[Gary Schafer]

On Sat, 22 Apr 2006 18:17:53 +0100, "Dave Plowman (News)"
<dave@davenoise.co.uk> wrote:

In article <fkgv32hadmm7s85ehgp864md13fojtdlmg@4ax.com>,
Gary Schafer <gaschafer@comcast.net> wrote:
Actually if a battery only shows "12 volts" it is near dead!

Not so. 11.5 should start the average car on an average day.

A standard wet cell battery will exhibit approximately the following
voltages at various states of charge at 70 degrees F: Courtesy of
William Darden's Battery faqs.

100% 12.643

75% 12.443

50% 12.273

25% 12.053

0% 11.883

Maintenance free batteries will be approximately the following:

100% 12.793

75% 12.593

50% 12.393

25% 11.993

0% 11.793

Regards
Gary

 

[chuck]

Gary Schafer wrote:

On Sun, 23 Apr 2006 12:54:56 GMT, chuck <nospam@nospam.net> wrote:


Keith wrote:

On Thu, 13 Apr 2006 22:17:49 +0000, chuck wrote:



Andy wrote:


I am in the UK and have a 1.3 litre Mazda which is over 10 years
old.

I have been reading a few web pages which made reference to the
reader's car which "may have a dashmoard voltmeter".

Is a voltmeter actually all that useful to see tjings like what
the condition the battery is in and how the battery copes and how
it is charging?

Can I permanently connect my cheap handheld digital voltmeter to
the car battery. I would then mount the meter permanently on the
dashboard.

Is there a real danger that the meter will get damaged by various
current or voltage surges? Is it good enough protection to have a
quick blow fuse in line with the test lead going to the positive
terminal?

Thanks




Don't bother with a voltmeter. A far better investment is a set of
jumper cables.


That's kinda like suggggesting one wear Depends instead of stopping at the
a rest area on the highway.



Nothing of the sort, really. If one is curious about battery charging
and discharging principles, then a voltmeter, ammeter, thermometer,
hydrometer, a lot of time, and a text book will prove rewarding.

But if the concern is to obtain early warning of an impending
battery/alternator/regulator/belt failure so as to avoid being caught on
the road without an electrical system, then most of us would benefit far
more from the jumper cable. ;-)

If the voltmeter would "prevent" such a breakdown by giving advance
warning of sufficiently high certainty to result in an immediate trip to
a competent repair technician, then it would be a good thing.
Unfortunately, even if the meter did so indicate, immediately and
unambiguously, one might be on the road far from any repair facilities
at the time of the indication, in which case jumper cables would be most
useful.

I wonder how many of us have looked at a voltmeter, concluded that
something was wrong, replaced the battery, and found that the world was
good again. Compare that number to those of us who, upon noticing a
strange reading of the meter, made a mental note to keep an eye on the
meter, and then eventually found ourselves with a dead battery. From the
postings, it seems not all of us would be able to interpret various
meter indications even if we had them before us.

Unlike the rest area "fix", a voltmeter will not "ward off" a leaking
battery failure. ;-)

Chuck


We might just as well throw out the fuel gauge then too. Just looking
at it will not keep us from running out of fuel. Might be better to
just carry a spare can of with us.

Like the voltmeter, if one doesn't know how to interpret the fuel
gauge properly it does no good to have it aboard. Admittedly the
voltmeter is a little more complicated to interpret than the fuel
gauge but it can also be a valuable instrument.

Regards
Gary

Hello Gary,

Sorry, but I think the gas gauge analogy is pretty weak. Voltmeter
readings are much more difficult to interpret. Can you imagine a thread
like this one on interpreting gas gauge readings? ;-)

Many autos have been sold without voltmeters and many have been sold
without fuel gages (VW for many years). My car has both an idiot light
and a gauge for fuel (for volts as well, actually) but I pay much closer
attention to the fuel gauge idiot light.

Many automotive voltmeters lack sufficient precision to be useful (mine
has a number at each end of the scale and one in the middle, with the
needle width approximately equal to the difference between 50% and full
charge! When bored on long trips I tend to ponder whether the scale is
actually linear. I find this activity even more boring and quickly take
a renewed interest in traffic.).

I do think it is very difficult for a typical driver to extract more
useful information from a typical voltmeter than from an idiot light.


Chuck

 

[Keith]

On Sun, 23 Apr 2006 12:11:09 +0100, Steve Firth wrote:

Keith wrote:

[snip]
Don't bother with a voltmeter. A far better investment is a set of
jumper cables.

That's kinda like suggggesting one wear Depends instead of stopping at the
a rest area on the highway.

Can you say that again in English?

A few hints for the E2Ler:

"Depends" = (http://www.depend.com/)

"rest area" ~
(http://www.ronsaari.com/stockImages/roadsideAttractions/nebraskaRestArea.php)

"highway" = http://www.schweich.com/imagehtml/1340_3152_4275_47sm.html

--
Keith

 

[Dave Plowman (News)]

In article <AOK2g.7634$Es3.6871@newsread3.news.atl.earthlink.net>,
chuck <nospam@nospam.net> wrote:

But if the concern is to obtain early warning of an impending
battery/alternator/regulator/belt failure so as to avoid being caught on
the road without an electrical system, then most of us would benefit far
more from the jumper cable. ;-)

What good is a jumper cable if your alternator/regulator/fanbelt has
failed on the road? You'd need a breakdown service to fix it and they all
carry starter batteries.

--
*Avoid clichés like the plague. (They're old hat.) *

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[PC Paul]

Dave Plowman (News) wrote:

In article <AOK2g.7634$Es3.6871@newsread3.news.atl.earthlink.net>,
chuck <nospam@nospam.net> wrote:
But if the concern is to obtain early warning of an impending
battery/alternator/regulator/belt failure so as to avoid being
caught on the road without an electrical system, then most of us
would benefit far more from the jumper cable. ;-)

What good is a jumper cable if your alternator/regulator/fanbelt has
failed on the road? You'd need a breakdown service to fix it and they
all carry starter batteries.

Once you've started with a jump either a battery OR an alternator+regulator
will get you home.

Unless you found out about the problem because it wasn't charging and now
it's run out...

 

[Dave Plowman (News)]

In article <K8udnchHb8MpMtbZRVnygQ@brightview.com>,
PC Paul <me@home.com> wrote:

What good is a jumper cable if your alternator/regulator/fanbelt has
failed on the road? You'd need a breakdown service to fix it and they
all carry starter batteries.

Once you've started with a jump either a battery OR an
alternator+regulator will get you home.

So you carry spares for these as well as jump leads?

Unless you found out about the problem because it wasn't charging and
now it's run out...

Yes. With no charge, jumping starting the car (because the battery is
flat) won't leave it running for long.

I do carry jump leads and a spare fan belt on the old car, though.

--
*It's o.k. to laugh during sexŒ.Œ.just don't point!

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Michael A. Terrell]

"Dave Plowman (News)" wrote:

In article <K8udnchHb8MpMtbZRVnygQ@brightview.com>,
PC Paul <me@home.com> wrote:
What good is a jumper cable if your alternator/regulator/fanbelt has
failed on the road? You'd need a breakdown service to fix it and they
all carry starter batteries.

Once you've started with a jump either a battery OR an
alternator+regulator will get you home.

So you carry spares for these as well as jump leads?

Unless you found out about the problem because it wasn't charging and
now it's run out...

Yes. With no charge, jumping starting the car (because the battery is
flat) won't leave it running for long.

I do carry jump leads and a spare fan belt on the old car, though.

--
*It's o.k. to laugh during sexŒ.Œ.just don't point!

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

I used to have a spare alternator on my 1966 GTO. I blew the front
bearing out so often that I got the bracket for that Pontiac 389 CID
engine with an AC compressor, which required the Alternator to moved to
the other side of the engine. Over rev the alternator, stop, remove the
fan belt and plug from the bad alternator, plug it into the spare and
install the fan belt on that side. A one minute or less repair on the
side of the road. I also used #1 AWG welding cable on the main battery
to reduce the voltage drop.


On other vehicles I've had a dual charging system and a pair of the
biggest batteries that would fit under the hood. Need a jump? Flip a
switch to tie the two batteries together with a starter solenoid and
start the engine.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Michael A. Terrell]

Gary Schafer wrote:

On Sat, 22 Apr 2006 18:17:53 +0100, "Dave Plowman (News)"
dave@davenoise.co.uk> wrote:

In article <fkgv32hadmm7s85ehgp864md13fojtdlmg@4ax.com>,
Gary Schafer <gaschafer@comcast.net> wrote:
Actually if a battery only shows "12 volts" it is near dead!

Not so. 11.5 should start the average car on an average day.

A standard wet cell battery will exhibit approximately the following
voltages at various states of charge at 70 degrees F: Courtesy of
William Darden's Battery faqs.

100% 12.643

75% 12.443

50% 12.273

25% 12.053

0% 11.883

Maintenance free batteries will be approximately the following:

100% 12.793

75% 12.593

50% 12.393

25% 11.993

0% 11.793

Regards
Gary

Is that a static voltage reading, or with the engine running and
charging the battery? Where is your voltmeter connected into the car's
wiring? How often is it 70 degrees F under your hood when you want to
check the voltage? Too many variables to get a useful answer with a
simple meter.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[PC Paul]

Dave Plowman (News) wrote:

In article <K8udnchHb8MpMtbZRVnygQ@brightview.com>,
PC Paul <me@home.com> wrote:
What good is a jumper cable if your alternator/regulator/fanbelt has
failed on the road? You'd need a breakdown service to fix it and
they all carry starter batteries.

Once you've started with a jump either a battery OR an
alternator+regulator will get you home.

So you carry spares for these as well as jump leads?

Unless you found out about the problem because it wasn't charging and
now it's run out...

Yes. With no charge, jumping starting the car (because the battery is
flat) won't leave it running for long.

So how did I get 100 miles in a 3.0 Supra with *no battery at all* in it
then?

An alternator is quite capable of giving enough current to keep the systems
going. Probably not on full beam, heated windows etc., but for daytime
running it was fine.

Don't stall it though.

I do carry jump leads and a spare fan belt on the old car, though.

 

[Dave Plowman (News)]

In article <KNednaQs-JIXXtbZRVnyuQ@brightview.com>,
PC Paul <me@home.com> wrote:

Yes. With no charge, jumping starting the car (because the battery is
flat) won't leave it running for long.

So how did I get 100 miles in a 3.0 Supra with *no battery at all* in it
then?

The alternator was working. I was talking about when the charging system
or fan belt fails. Jump leads won't help you then.

An alternator is quite capable of giving enough current to keep the
systems going. Probably not on full beam, heated windows etc., but for
daytime running it was fine.

The voltage from an unterminated alternator can go sky high and fry the
electronics. Not recommended.

Don't stall it though.

--
*When you've seen one shopping centre you've seen a mall*

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Gary Schafer]

On Sun, 23 Apr 2006 17:58:15 GMT, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

Gary Schafer wrote:

On Sat, 22 Apr 2006 18:17:53 +0100, "Dave Plowman (News)"
dave@davenoise.co.uk> wrote:

In article <fkgv32hadmm7s85ehgp864md13fojtdlmg@4ax.com>,
Gary Schafer <gaschafer@comcast.net> wrote:
Actually if a battery only shows "12 volts" it is near dead!

Not so. 11.5 should start the average car on an average day.

A standard wet cell battery will exhibit approximately the following
voltages at various states of charge at 70 degrees F: Courtesy of
William Darden's Battery faqs.

100% 12.643

75% 12.443

50% 12.273

25% 12.053

0% 11.883

Maintenance free batteries will be approximately the following:

100% 12.793

75% 12.593

50% 12.393

25% 11.993

0% 11.793

Regards
Gary

Is that a static voltage reading, or with the engine running and
charging the battery? Where is your voltmeter connected into the car's
wiring? How often is it 70 degrees F under your hood when you want to
check the voltage? Too many variables to get a useful answer with a
simple meter.

http://www.batteryfaq.org/SoC.xls

Regards
Gary